But adding edible serving size markers that act as subconscious stop signs to snack food items could re-educate Americans’ on portion size and reduce tendencies to overeat, according to two experiments conducted by researchers at Cornell University.

In the [first] study, researchers divided 98 students into two groups. The students were given tubes of chips — some divided by red-dyed “stop sign” chips, others not — then settled down to watch movies. Interestingly, the chips were counted differently; in some tubes the marker chips were inserted after every 7 chips; in others after every 14 chips. The researchers, who were part of Cornell’s Food and Brand Lab, then counted the number of chips each student ate.

… [Researchers] found that the students given the tubes with the marked chips ate on average half the number of chips as the students given the unmarked tubes. The students didn’t receive any explanation of why some of the tubes contained red chips. Even so, the students given the marked chips ate 20 and 24 chips on average (for the seven-chip and 14-chip tubes, respectively), compared with 45 chips in the control group.

During the second study, which has not been published, the food markers were placed after every five or 10 chips. Results showed that participants’ whose tubes had a marker after every five chips ate 14 chips and those with markers placed after every 10 chips ate 16 chips. But volunteers in the control group consumed 35 chips.

The investigators say additional research is needed to better understand how such segmentation cues work, why they work and whether people will compensate for the reduction in food intake by eating more later.